Parallel string installation for single-zone production



Aug. 1, 1967 J 5 P G ET AL 3,333,639

PARALLEL STRING INSTALLATION FOR SINGLE-ZONE PRODUCTION Filed Nov. 27, 1964 O f 200 .in

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Aug. 1, 196 7 J PAGE ET AL PARALLEL STRING INSTALLATION FOR SINGLE-ZONE PRODUCTION Filed Nov. 27, 1964 E60 20.

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Aug. 1, 1967 J PAGE ET AL PARALLEL STRING INSTALLATION FOR SINGLE-ZONE PRODUCTION Filed Nov. 27, 1964 5 Sheets-Sheet 5 $0 .pflGE: kipa INVENTORS V flrraeA/svs.

United States Patent M 3,333,639 PARALLEL STRING INSTALLATION FOR SINGLE-ZONE PRODUCTION John S. Page and John S. Page, Jr., both of 1450 El Mirador, Long Beach, Calif. 90815 Filed Nov. 27, 1964, Ser. No. 414,141 19 Claims. (Cl. 166-420) ABSTRACT OF THE DISCLOSURE The disclosed assembly includes a generally parallel pair of tubing strings and barrier structure received downwardly in a well bore; first means carried by the assembly to plug one string and to be responsive to fluid pressure in that string for controlling flow of fluid upwardly between zones below and above the barrier and outside the strings; and second means carried by the assembly in the well to restrict upward flow of fluid in the other string.

This invention relates generally to the control of fluid flow in wells, and more particularly concerns the utilization of dual or parallel tubing strings in a well to control the flow of production fluid between a well zone next below barrier stmcturein the well and the surface.

It is a major object of the invention to provide a way to control production flow of fluid from a lower zone next below a barrier in a well to the surface, and at the same time to facilitate independent injection of fluid to that lower zone. Such injection may typically be desired where the production from that zone is to be started, killed or the zone treated as by steam or acid injection. It is a further object of the invention to achieve control of production flow and said injection in such a way that auxiliary pressure control lines outside tubing strings are not needed.

The needs made evident by these objects are met in a novel and unusual manner in accordance with the invention through the provision of a basic well assembly including a generally parallel pair of tubing strings and barrier structure received downwardly in the well bore and through which the strings communicate vertically, first means carried by the string and barrier assembly to be responsive to fluid pressure in one string for controlling upward flow of well fluid between zones above and below the barrier structure and outside the strings, and second means canied by the string and barrier assembly in the well to restrict upward flow of fluid in the other string. As will appear, said second means may typically comprise a retrievable check valve within and having releasable attachment to the other string, in order that injected fluid may at times be passed downwardly to the zone below the barrier, while upward flow of production fluids is at all times blocked or plugged by the check valve. The first means may typically comprise a retrievable valve located in flow plugging relation with the first string for exposure to diiferenti-al pressure exerted by well fluid above and below the valve, and it is preferably responsive' to a predetermined change in differential pressure .for controlling the upward flow of well fluid between a lower zone below the barrier structure and an upper zone above the barrier structure, =both zones being outside the strings. The barrier structure itself typically includes packing and anchor elements urged into packing rod anchoring engagement with the well bore in response to exertion of predetermined pressure of well fluid flowing upwardly at the barrier.

3,333,639 Patented Aug. 1, 1967 In its method aspects, the invention involves the control of production fluid flow in a well containing first and second tubing strings and a barrier, the operative steps of the method including flowing production fluid upwardly in the first string from a zone next below the barrier for continued upward flow in the well in such manner that the upwardly flowing fluid passes a pressure differential responsive control valve, subjecting said valve to a pressure differential created by transmission thereto of production fluid pressure and the opposing pressure of control fluid in the string above the valve, varying said control fluid pressure to operate the control valve, and

V injecting other fluid downwardly through the second string and past the barrier to said zone for treating said zone independently of the production flow through the first string. In addition, the control pressure to operate the control valve may be varied by boosting the pressure of the production fluid delivered at the well head and controllably applying said boosted pressure to the control fluid in the first string, or by controllably venting the control fluid pressure within the first string at the well surface to eflect opening of the valve.

These and other objects and advantages of the inven :tion, as well as the details of illustrative embodiments, will be more fully understood from the following detailed description of the drawings in which:

FIG. 1 is an overall view of an installation made in accordance with the invention;

FIGS. 2a, 2b, and 2c are enlarged vertical sections taken through the novel dual string and barrier assembly in the well, the production flow control valve being Open;

FIG. 3 is a view like FIG. 2a showing the production flow control valve closed;

FIG. 4 is a section taken on lines 4-4 of FIG. 2c; and

FIG. 5 is a section taken on lines 55 of FIG. 2c.

Referring to FIG. 1, the invention is illustrated as installed, with well casing 10 extending downwardly into the formation 11 and perforated at 12 to establish communication between the productive formation 11 and the lower zone 13 within the interior of the casing. Located within the casing is an assembly generally designated at 14 and including a generally parallel pair of tubing strings 15 and 16, together with barrier structure 17 which is received downwardly in the bore 18 of the casing, the strings 15 and 16 communicating vertically through the barrier structure. As will later appear, well fluid is controlled to flow upwardly from the lower zone 13 next below the barrier structure 17 to an upper zone 19 which lies outside the strings 15 and 16. Production flow in the upper zone or annulus 19 reaching the well head is taken off through a line 20 which is valve controlled at 21 for delivery at 22.

The well head equipment illustrated also includes lines 23 and 24 which are valve controlled at 25 and 26 to communicate respectively with upward extensions 27 and '28 of the strings 15 and 16, there also being a valve 29 in series with the extension 27. As will appear from the following description, string 16 may be considered as the long or injection string through which fluid may be injected downwardly from a source 30 to pass through the barrier structure 17 to a perforated lower extension 16a communicating with the lower zone 13 within the casing. Control fluid may be passed from a source 31 to line 23 and to the first string 15 for controlling the opera tion of first means carried by the assembly 14, said first means then operating to control upward flow of well fluid duction fluid pressure through a unit 33 and then to a line '34 returned to the upper extension 27 of the first string 15.

7 Unit 33 may incorporate a check -valve to pass the pressure toward the first string but not to permit reverse communication of such pressure to the production flow in line 20. Unit 33 may also provide for venting of the control pressure at 34a or for boosting of the control pressure as by means of the boost mechanism 35.

Extending the description to FIGS. 20, 2b and 2c, the a barrier structure 17 typically includes a body made up of several body sections, in such manner that the body issuspended in the well by one or both of the strings 15 and 16. For example, the upper body section 35a is seen in FIG. 2b to have thread connection at 36 and 37 with the pin terminals of the strings 15 and 16. Body section 35a contains parallel bores 38 and 39 communicating with the respective strings, and it may be considered as a crossa over member in the assembly. An intermediate body section 40 has'thread connection 41 to the upperbo'dy section 35a and defines an enlarged bore 42 below the bores 38 and 39. A lower continuation 42a of said enlarged bore is defined by a lower body section 43 having thread connection to section 40at 44.

Examination of FIGS. 2b and 20 will first string 15 communicates with the lower zone 13 next below the barrier structure via the bore 42 and its continuation 42a, whereas the lower extension 16:: of the string 16 extends downwardly through the 'bore'42 to a show that the point well below the barrier structure 17 before'it openly communicates, with a lower level 13a of the zone 13, as afforded by the perforations 44 in the lower extension 16a. Accordingly, the first string 15 directly communicates with an upper portion of the zone'13, whereas the second.

string 16 communicates with a lower portion of that zone. In this regard, tubing extension 16a may have thread connection at 45 with the body section 35a torbe suspended therefrom.

Referring now to FIGS. 2a and .3, the assembly, and specifically the string '15 directly above the barrier structure, has side porting through which production fluid is flowable as indicated by the arrow 51 in FIG. 2a, the

.porting establishing communication between the lower' zone 13 and the upper zone 19. In this regard, the porting 50 may be formed in a sub 52 which is considered as a part of the string 15. Contained within the sub 52 is what ,may be considered as first means responsive to fluid pressure in the string 15 for controlling upward flow of pro:

duction fluid through the porting 50, i.e. between the zones 13 and 19 respectively below and above the barrier structure 17 and outside the strings. The first means 53 is located in flow plugging relation with the sub 52 for exposure to pressure exerted by well fluid above and be-' low'the means 53, all in such manner that it is responsive to a predeterminedchange in thepressure differential for controlling the upward flow of production fluid through V the port 50. 7 e

' In the embodiment illustrated, avalve member 54 is suspendedby a stem 55 and a carrier 56, a vertical mandrel 57 being attached to the carrier. The mandrellhas a head 58 which is engageable with an internal flange 59 carried by a collet unit 60 to limit downward travel of the valve member of plug 54.-relative to the collet. The

latter has spring fingers 61 carrying latch dogs 62 which are vertically movable within grooving 63 formed in the sub 52. The collet supports the valve member for telescopic movement relative thereto, with the mandrel 57 moving vertically through the bore 64 of the collet flange 59. Accordingly, upward travel of the valve member 54 in closed position, as seen in FIG. 3, is limited by engage 'ment of the upper shoulder 65 of the carrier 56 with the Downward pressure of control fluid within the string 15 is exerted on the mandrel head 58 and on the carrier, as for example on the surfaces 68 and 69 thereof, in order to urge the valve member 54 downwardly toward open position. Upward pressure tending to close the valve member is applied against the under surface 70 of the valve member plug 54. Pressure applied against the plug and carrier annular surfaces 71 and 72 is balanced due to the equal areas of these surfaces. Accordingly, if the control pressure in the string 16 above the mandrel head 58 is suflicient, it dominates in relation to the upward pressure exerted against the plug surface 70, whereby the valve plug moves downwardly to open position. On the other hand, if the pressure applied against surface 70 is sufli cient in relation to the downward pressure in the string 15 above the mandrel head 68, it dominates the valve plug to move it upwardly to closed position.

A lower seal ring is carried at 73 and the plug 54 when the valve member is in seated position as seen in FIG. 3. An upper seal ring 75 is carried and confined to seal off at all timesbetween the carrier 56 and the inwardly facing bore 77 of sub 52, in order that the first means 53' may effectively plug'the sub by blocking access of the control fluid inthe string 15 above the mandrel head 58 to the side porting'50. V 7

Second means is also carried by the assembly 14 in the well to restrict upward flow of fluid in the other or second string 16. Typically, as seen in FIGS. 2a and.

3, said second means comprises a retrieval check valve unit 80 having releasable attachment to the second g string, as for example, in the second string sub' 81. The 7 unit 80 is shown to comprise a body 82 receivable downwardly within the bore 83 of the sub andihaving sealing'engagement therewith at 84. Contained within-the body is a seat 85 facing downwardly to receive upward engagement of a ball plug 86 urged upwardly by a compression spring 87. The latter 'is fitted between the ball and an inward flange 88 on a sleeve 89. received within the body 82. The latter carries a collet 90 having spring fingers 91 with latch dogs 92 which are spreadable'into the grooving 93 in. the bore of the sub 81. The collet fingers 91, .and 'the collet fingers-61, respectively carry serrated terminals 94 and 95 adapted to be gripped by retrieving tools lowered'by wire line within the strings to engage said terminals and retract the fingers inwardly such' a allowing upward retrieval. The tubular head of tool is seen at 200 in FIG. 2a.

In operation, fluid injecteddownwardly within string. 16, as controlled by valve 26 in FIGJI, passes through the check Valve unit and through the barrier structure .17 to exit from the string lower extension 16a and a lower portion of the zone 13, i.e. portion 13a. This operation can be carried'out independently of flow of production j fluid upwardly via string 15 and port 50 to the annulus 19. In addition, the check valve unit prevents upward flow of production fluidwithin the string 16 above the check valve.

FIGS. 2b, 2c, 4 and 5illustrate the provision or a type' of barrier structure thatincludes packing and anchor elements as well as actuator structure to urge said elei ments into packing and anchoring engagement with the under surface 66 of the collet flange 59. At this time 7 the collet dogs engage the upper limit 67 of the grooving 63. V V

well bore, i.e. the bore 18 of the casing, in response to exertion on the actuator structure of predetermined pressure of well fluid flowing upwardly within the bore 42 and 42a of the barrier. In the example illustrated,

by the plug to seal oif and become confined between the annular seat 74' peripheries 108 with the casing bore 18. The serrations are angled to bite the casing bore for resisting downward displacement of the barrier including the packer 109 carried by the body section 43. In this regard, the packer is compressed between the cone 107 and a ring 110, the latter bearing against the under surface 111 of the body section 40. It is seen that the cone 107 is slidable upon the surface 112 of the body section 43 in order that the packer 109 may be compressed axially and spread outwardly to seal otf at 113 against the casing bore.

Finally, the body section 40 contains side openings 114 receiving anchor plugs 115 having their piston surfaces 116 exposed to the pressure of fluid within the bore 42. The outer peripheries of the pistons are serrated at 120 with angularity to bite into the casing bore for resisting upward displacement of the barrier structure including the packer 109. O-ring seals 117 seal oflf between the piston plugs 115 and the side openings 114 during piston radial travel. A pilot or guide ring 130 is carried at the lowermost portion of body section 43 to engage the casing bore for piloting the downward movement of the assembly in the casing.

FIGS. 1 and 2b also show the provision of a generally vertical passage 130 through the body section 35a,'the passage being olfset from the vertical openings 38 and 39, yet overlying the bore 42 of intermediate body section 40. A pipe protected instrumentation line or cable 131 is connected to the assembly, as by clamps or retainers 132 on string 16, the line extending from the well surface downwardly through the passage 130 and to a point below the barrier structure. As seen in FIG. 1, a bottom hole pressure sensor 133 is typically connected to the line 131 in zone 13a, and transmits bottom hole pressure signals via the line 131 to the surface. A pressure recorder 136 is connected to the line 131 at the surface for recording the bottom hole pressure signals electrically transmitted upwardly via the line 131. A packing gland is indicated at 135 in FIG. 2b for sealing off between the line 131 and the body section 35a.

We claim:

1. In combination in a well, an assembly including a generally parallel pair of tubing strings and barrier structure received downwardly in the well bore and through which the strings communicate vertically, first means carried by said assembly to be responsive to fluid pressure in one string for controlling upward flow of well fluid between zones below and above said barrier structure and outside said strings, said assembly having a port through which the flow of well fluid between said zones is controlled by said first means, said first means being located in flow plugging relation with said one string for exposure to pressure exerted by well fluid above and below said first means, whereby said first means is responsive to a predetermined change in at least one of said pressures for controlling the upward flow of well fluid through said port, and second means carried by the assembly in the well to restrict upward flow of fluid in the other string.

2. The combination of claim 1 in which said second means comprises a retrievable check valve having releasable attachment to said other string.

3. The combination of claim 1 in which said barrier structure is suspended in the well by said one string and has a bore through which the other string extends vertically.

4. The combination of claim 1 including supports for each of said first and second means and having releasable atachment with said strings, said first and second means being retrievable upwardly within said strings.

5. The combination of claim 1 including means at the well head to establish fluid pressure transmission from the well annulus above said barrier structure to the interior of said one string for utilizing said pressure transmission in the corfirol of said first means.

6. The combination of claim 1 in which said barrier structure includes packing and anchor elements and actubody contains another generally vertical passage therethrough, and including an instrumentation line connected to said assembly and extending from the well surface downwardly through said body passage and to a point in the well below said barrier structure.

9. The combination as defined in claim 8 including a well pressure sensor connected to said line below said barrier structure and a recorder connected to said line at the well surface.

10. In combination in a well, an assembly including a generally parallel pair of tubing strings and barrier structure received downwardly in the well bore and through which the strings communicate vertically, first means for controlling upward flow of well production fluid between zones above and below said barrier structure and outside said strings, one string having a side port through which said upward flow of well fluid is flowable, an annular seat located in said'one string to pass production fluid flowing to said port, said first means being in said one string and connected in plugging relation therewith to be exposed to upward thrust transmitted by the upwardly flowing production fluid-and also to communicate with the string interior above said first means so as to be responsive to a change in the static pressure of string interior control fluid for controlling said flow of production fluid, said means including a valve member movable generally vertically between seated and unseated positions to effect said flow control, said member having a surface located to receive thrust applied thereto in response to downward exertion of string interior control fluid pressure, whereby control of valve member movement between said positions to control the upward floW of well production fluid may be efiected by changing the string interior control fluid pressure applied downwardly at'said surface, and second means carried by the assembly in the well to restrict upward flow of fluid in the other string.

11. The combination of claim 10 in which said first means includes a collet having spring fingers inside the housing and releasably attached thereto, the collet supporting the valve member for telescopic movement relative thereto.

12. In combination in a well, a well casing, an assembly including a generally parallel pair of tubing strings and barrier structure received downwardly in the casing bore and through which the strings communicate vertically, first means carried by said assembly for controlling upward flow of well fluid in one string, said assembly having a port through which the flow of well fluid between said zone lower than said barrier structure and an upper well zone above said barrier structure is controlled by said first means, said upper well zone being outside said strings, said first means being located in plugging relation with said one string for exposure to pressure exerted by well fluid above and below said first means, whereby said first means is responsive to a predetermined change in at least one of said pressures for controlling the upward flow of well fluid through said port, second means carried by said assembly to restrict upward flow of fluid in the other string but pass downward flow of fluid therein, both strings having communication with the well zone ouside said strings and next below said barrier structure, said other string extending vertically below said barrier structure and below the ble attachement to saidother string.

lower terminal of said one string so that said one string directly communicateswith an upper portion of said zone and said other string cornmunncates with a lower portion of said zone. l

13. The combination of claim 12 in which said second means comprises a retrievable check valve having releasa- 14. The combination of claim 12 in which said barrier structure is suspended in the well by said one string and has a bore through which the other string extends vertically.

15. The combination of'claim 12 including supports for each of said first and second means and having releasable attachment with said strings, said first and second means being retrievable upwardly within said strings.

, 16. The combination of claim 12 including means at the Well head to establish fluid pressure transmission from the'well annulus above said barrier structure to the interior of said one string for utilizing said pressure transmission in the control of said first means.

'17. The combination of claim 12 in which said barrier structure includes packing and anchor elements and actuator structure to urge said elements into packing and anchoring engagement with the well bore in response'to exertion on the actuator structure of predetermined pressure of well fluid flowing upwardly at the barrier and toward said side port.

18. In combination in a well, an assembly including a generallyparallel pair of tubing strings and barrier structure received downwardly in the well bore and through which the strings communicate vertically, first means carried by said assembly to be responsive to fluid pressure in one string for controlling upward flow of well downwardly through'said body passage and to a point" in the well below said barrier structure.

fluid 'between'zones below and above'said barrier structure and outside said strings,- and second means'carried by the assembly in the well to restrict upward flow of fluid in the other string,'said barrierstructure including a body connected with said tubing strings andcontaim ing generally parallel openings therethrough to pass string fluid generally vertically through said body, said body. also containing another generally vertical passage there through, and including an instrumentation line connected to said assembly and extending from the well. surface.

19. The combination as defined in claim 18 including a well pressure sensor connected .to said line below said barrier structure and a recorder" connected to said line at the well surface.

References Cited UNITED STATES PATENTS CHARLES E. OCONNELL', Primary Exdminer. JAMES A. LEPPINK, Examiner. 

1. IN COMBINATION IN A WELL, AN ASSEMBLY INCLUDING A GENERALLY PARALLEL PAIR OF TUBING STRINGS AND BARRIER STRUCTURE RECEIVED DOWNWARDLY IN THE WELL BORE AND THROUGH WHICH THE STRINGS COMMUNICATE VERTICALLY, FIRST MEANS CARRIED BY SAID ASSEMBLY TO BE RESPONSIVE TO FLUID PRESSURE IN ONE STRING FOR CONTROLLING UPWARD FLOW OF WELL FLUID BETWEEN ZONES BELOW AND ABOVE SAID BARRIER STRUCTURE AND OUTSIDE SAID STRINGS, SAID ASSEMBLY HAVING A PORT THROUGH WHICH THE FLOW OF WELL FLUID BETWEEN SAID ZONES IS CONTROLLED BY SAID FIRST MEANS, SAID FIRST MEANS BEING LOCATED IN FLOW PLUGGING RELATION WITH SAID ONE STRING FOR EXPOSURE TO PRESSURE EXERTED BY WELL FLUID ABOVE AND BELOW SAID FIRST MEANS, WHEREBY SAID FIRST MEANS IS RESPONSIVE TO A PREDETERMINED CHANGE IN AT LEAST ONE OF SAID PRESSURES FOR CONTROLLING THE UPWARD FLOW OF WELL FLUID THROUGH SAID PORT, AND SECOND MEANS CARRIED BY THE ASSEMBLY IN THE WELL TO RESTRICT UPWARD FLOW OF FLUID IN THE OTHER STRING. 